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Disproportionation of PtPh(CH2COMe)(cod) and Conproportionation of PtPh2(cod) and Pt(CH2COMe)2(cod) via Intermolecular Phenyl Ligand Transfer

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journal contribution
posted on 26.10.2002, 00:00 by Yuji Suzaki, Takeyoshi Yagyu, Yuichi Yamamura, Atsunori Mori, Kohtaro Osakada
PtI(Ph)(cod) (cod = 1,5-cyclooctadiene)reacts with acetone in the presence of Ag2O to give a mixture of Pt(CH2COMe)(Ph)(cod) (1), PtPh2(cod) (2), and Pt(CH2COMe)2(cod) (3) in a molar ratio of 61:20:19. Complex 1, having the phenyl and acetonyl ligands, was isolated by recrystallization of the products and characterized by X-ray crystallography. The reaction of AgBF4 with PtI(Ph)(cod) forms [PtPh(cod)(acetone-d6)]BF4 and does not give a diarylplatinum complex. Thus, Ag2O, in the reaction of PtI(Ph)(cod) with acetone, promotes activation of both the Pt−I bond of PtI(Ph)(cod) and a C−H bond of acetone. Heating of 1 in acetone at 50 °C causes its partial disproportionation into 2 and 3 to give a mixture of the above three complexes. An equimolar mixture of 2 and 3 in acetone undergoes conproportionation into 1 at 50 °C to give a mixture of the complexes. The conproportionation is completed in 30 h to form the mixture with [1]:[2]:[3] = 66:17:17, while the above disproportionation of 1 does not attain equilibrium even after 70 h. The disproportionation and conproportionation of these complexes are observed also in benzene at 50 °C.